I'd go ahead and finish the round of Maracyn II just so you don't accidentally breed something resistant, but I wouldn't start a second round regardless of anything. I don't think that's what he needs.

Your guy is a little clamped but that could just be stress from the meds. The tips of his fins are white but it looks like normal coloring? Or are you seeing something like this: http://www.google.com/imgres?q=ancho...0&tx=117&ty=39 I can't tell but one of the tips towards the bottom almost looks like an anchor worm. but it could just be the camera because the detail is pretty blown out. They'll be white and long with a v.

Otherwise I'm not really seeing anything odd.. unless you're saying his fins never had any of that white on it until 4 days ago.. I'd still venture that he's shedding excess slime coat from all that extra stress coat building chems you put in.

Yeah, that is just his normal coloring. But he is still darting into things, like the glass of the tank and his heater. Perhaps I should still treat him for parasites?

Maybe but I think first lets deal with his water. Stop the Ph drops, and acclimate to the native ph of the water. Test for ammonia after using prime and get him into some water that's treated. If he's still darting after that then I'd say treat for parasites. Darting can also be a problem with water quality and ammonia, but if that's not it then it's probably parasites.. though I'm not seeing any signs from the video maybe his coloring is masking it. Like if you turn off the light and shine a flashlight on him is anything yellow? Or can you see any sprinklings of salt? Also check his gills.. try to get him to flare and look under. It could also be internal so look at his poo and let me know if it's anything but brown and if it's too long and stringy.

Maybe but I think first lets deal with his water. Stop the Ph drops, and acclimate to the native ph of the water. Test for ammonia after using prime and get him into some water that's treated. If he's still darting after that then I'd say treat for parasites. Darting can also be a problem with water quality and ammonia, but if that's not it then it's probably parasites.. though I'm not seeing any signs from the video maybe his coloring is masking it. Like if you turn off the light and shine a flashlight on him is anything yellow? Or can you see any sprinklings of salt? Also check his gills.. try to get him to flare and look under. It could also be internal so look at his poo and let me know if it's anything but brown and if it's too long and stringy.

There are some sprinkles of gold, but I'm not sure if it's his natural coloring or not. I will keep an eye out for an increase in the metallic gold color just in case.

Another question: There has been white stringy cottony stuff floating around the tank lately. I would say that it may be from the food, but he eats every single pellet I drop. I don't drop another pellet until he eats it. It's growing on the heater and the decorations, too. What is it, and what should I do?

It could be worms and it could be him shedding his coat. When you do water changes make sure to rinse everything off and get all that out to be safe.

Gold dust is generally velvet.. especially if it's hard to see in the light but shining a flash light illuminates. That would definitely cause the flashing.

Still maintain what I said.. get water quality under control then treat with aq and heat if needed after that per the sticky instructions.

I will definitely do exactly what you told me to. I went out and got Prime, so that during my next water change, I can use it. However, there's just so much cottony stuff floating around in his tank...it's making his tank completely cloudy and just piling on his gravel, but I'm being reluctant to change his water because of the Maracyn-Two...